Fix developer key manual generation doc
Fix developer key manual generation doc

the current code doesn't work because of the attr_accessible on
DeveloperKey

Change-Id: Id6cf7a3eab5808c05c22c43e6095ab6011ec0f76
Reviewed-on: https://gerrit.instructure.com/12275
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Reviewed-by: Zach Pendleton <514dbb4d54d4f29e454990df7d075678f43f92aa@instructure.com>

leftplusrightllc/canvas-lms,samuels410/greatlakes-lms,leftplusrightllc/canvas-lms,wimemx/Canvas,djbender/canvas-lms,antoniuslin/canvas-lms,gbleydon/canvas-lms,utkarshx/canvas-lms,instructure/canvas-lms,shidao-fm/canvas-lms,va7map/canvas-lms,wye0220/shindig-canvas,arrivu/hoodemo,landonwilkins/canvas-lms,icelab/canvas,grahamb/canvas-lms,merichar/canvas-lms,sfu/canvas-lms,juoni/canvas-lms,jay3126/canvas-lms,venturehive/canvas-lms,Unow/canvas-lms,Rvor/canvas-lms,snehakachroo1/LSI_replica,ShreniiNepal/shrenii_lmp,tgroshon/canvas-lms,shidao-fm/canvas-lms,matematikk-mooc/canvas-lms,fronteerio/canvas-lms,whalejasmine/canvas-lms,ankithbti/canvas_lms,tgroshon/canvas-lms,sdeleon28/canvas-lms,arrivu/arrivu-lms,Jyaasa/canvas-lms,va7map/canvas-lms,arrivu/hiring-site,matematikk-mooc/canvas-lms,landonwilkins/canvas-lms,Jyaasa/canvas-lms,dgynn/canvas-lms,SwinburneOnline/canvas-lms,Unow/ins,usmschuck/canvas,sdeleon28/canvas-lms,efrj/canvas-lms,utkarshx/canvas-lms,shidao-fm/canvas-lms,icelab/canvas,kyroskoh/canvas-lms,samuels410/greatlakes-lms,Rvor/canvas-lms,wye0220/shindig-canvas,jay3126/canvas-lms,arrivu/jigsaw-lms,loganrun/pincan,sli7246/canvas_branch,loganrun/pincan,usmschuck/canvas,sfu/canvas-lms,ShreniiNepal/shrenii_lmp,arrivu/hiring-site,grahamb/canvas-lms,snehakachroo1/LSI_replica,arrivu/qibla-ecampus,gbleydon/canvas-lms,arrivu/jigsaw-lms,nditech/red-innovadores-lms,arrivu/hoodemo,grahamb/canvas-lms,djbender/canvas-lms,kyroskoh/canvas-lms,merichar/canvas-lms,parbros/red-innovadores-lms,leftplusrightllc/canvas-lms,efrj/canvas-lms,greyhwndz/canvas-lms,wimemx/Canvas,wrdsb/canvas-lms,samuels410/greatlakes-lms,merichar/canvas-lms,HotChalk/canvas-lms,dgynn/canvas-lms,venturehive/canvas-lms,dgynn/canvas-lms,skmezanul/canvas-lms,narigone/canvas,instructure/canvas-lms,roxolan/canvas-lms,gbleydon/canvas-lms,narigone/canvas,sfu/canvas-lms,sfu/canvas-lms,nditech/red-innovadores-lms,instructure/canvas-lms,arrivu/hiring-site,juoni/canvas-lms,ankithbti/canvas_lms,usmschuck/canvas,Jyaasa/canvas-lms,arrivu/arrivu-lms,whalejasmine/canvas-lms,AndranikMarkosyan/lms,skmezanul/canvas-lms,Rvor/canvas-lms,jay3126/canvas-lms,roxolan/canvas-lms,SwinburneOnline/canvas-lms,antoniuslin/canvas-lms,HotChalk/canvas-lms,va7map/canvas-lms,instructure/canvas-lms,fronteerio/canvas-lms,wimemx/Canvas,whalejasmine/canvas-lms,parbros/red-innovadores-lms,Jyaasa/canvas-lms,tgroshon/canvas-lms,kyroskoh/canvas-lms,nditech/red-innovadores-lms,arrivu/jigsaw-lms,sli7246/canvas_branch,nditech/red-innovadores-lms,HotChalk/canvas-lms,sli7246/canvas_branch,matematikk-mooc/canvas-lms,parbros/red-innovadores-lms,venturehive/canvas-lms,AndranikMarkosyan/lms,Unow/canvas-lms,wrdsb/canvas-lms,arrivu/qibla-ecampus,redconfetti/canvas-lms,arrivu/hoodemo,antoniuslin/canvas-lms,matematikk-mooc/canvas-lms,arrivu/arrivu-lms,juoni/canvas-lms,ShreniiNepal/shrenii_lmp,icelab/canvas,grahamb/canvas-lms,instructure/canvas-lms,whalejasmine/canvas-lms,Unow/canvas-lms,wrdsb/canvas-lms,HotChalk/canvas-lms,skmezanul/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,eCNAP/CANVAS,landonwilkins/canvas-lms,fronteerio/canvas-lms,redconfetti/canvas-lms,djbender/canvas-lms,AndranikMarkosyan/lms,roxolan/canvas-lms,Unow/ins,landonwilkins/canvas-lms,rup/Tarrax,samuels410/greatlakes-lms,greyhwndz/canvas-lms,rup/Tarrax,ankithbti/canvas_lms,snehakachroo1/LSI_replica,redconfetti/canvas-lms,leftplusrightllc/canvas-lms,grahamb/canvas-lms,ShreniiNepal/shrenii_lmp,venturehive/canvas-lms,jay3126/canvas-lms,Rvor/canvas-lms,skmezanul/canvas-lms,antoniuslin/canvas-lms,shidao-fm/canvas-lms,utkarshx/canvas-lms,loganrun/pincan,SwinburneOnline/canvas-lms,efrj/canvas-lms,usmschuck/canvas,kyroskoh/canvas-lms,sfu/canvas-lms,eCNAP/CANVAS,va7map/canvas-lms,instructure/canvas-lms,narigone/canvas,roxolan/canvas-lms,juoni/canvas-lms,sdeleon28/canvas-lms,sfu/canvas-lms,rup/Tarrax,eCNAP/CANVAS,narigone/canvas,greyhwndz/canvas-lms,utkarshx/canvas-lms,snehakachroo1/LSI_replica,Unow/ins,wye0220/shindig-canvas,redconfetti/canvas-lms,eCNAP/CANVAS,sdeleon28/canvas-lms,greyhwndz/canvas-lms,wrdsb/canvas-lms,instructure/canvas-lms,efrj/canvas-lms,fronteerio/canvas-lms,SwinburneOnline/canvas-lms,arrivu/qibla-ecampus,dgynn/canvas-lms,tgroshon/canvas-lms,AndranikMarkosyan/lms